System and Method for Digital Program Insertion in Cable Systems

ABSTRACT

Alternative approaches to the insertion of local commercials and messages into networks feeds are provided. Embodiments include digital commercial insertion for cable operators and others that not only offer more flexibility and features, but may also be significantly cheaper to implement. The actual “insert” of the local commercial or message into the digital program is performed by a standard set top box, with several methods of providing the local commercial to the set top box at the proper insertion time. Another embodiment allows a cable operator to significantly save on equipment in the form of splicers and ad inserters, by allowing easy and dynamic mapping of local commercials to insertion zones.

RELATED APPLICATION

The present application claims the benefit of U.S. Provisional Application No. 60/600,664 filed on Aug. 11, 2004, which is incorporated herein by reference.

FIELD OF THE INVENTION

This invention is directed towards digital media transmission, and more particularly towards transmission of digital programs to end viewers.

BACKGROUND

Cable operators use their infrastructure to carry programming content and deliver (sell) this to their subscribers. As part of their agreements with some programmers, the cable operator can also be allowed to insert commercial messages in those network feeds. The operator is typically allowed to do that only at selective times (sometimes called “local avails”, “avails”, “local breaks”, or “breaks”), typically 1-3 minutes per hour. The operator can choose to either sell this time to advertisers (generating extra revenue), or use the time to insert promotional messages for their own products and services.

Cable operators have used the following set up illustrated in FIG. 1 to implement local commercial insertion. The programmer typically distributes their feed via satellite 22 to the various cable operators. The feed can be analog or even digitally encoded. The feed contains signals (in the form of audio tones called “cue tones”) that indicate a local break to the cable operator.

The receiver at the cable operator receives the satellite signal 20 (decompresses it in case of a digital signal), strips off the audio tone, passes through the (analog) feed 24 to the ad inserters 26, and (separately) passes the Insertion (Control) Signal 25 to the ad inserter as well (triggered by the cue tone in the feed). The Traffic & Billing system 28 is responsible for scheduling the commercial messages across the day, it feeds schedule files to ad inserters 26 (typically once a day) with today's insertion schedules.

Separately (and typically at least one day before airing), the commercial messages are loaded into the ad inserters 26 (this can be encoded from tape, or transcoded from a digital format).

The ad inserter 26 as shown in FIG. 2A typically just “passes through” the incoming analog feed, but whenever it gets an “insert” signal, as shown in FIG. 2B, it looks in its schedule to see which message should be inserted, then looks up the message in its internal database 30, and inserts the message into the (analog) feed.

Messages can be any length (as long as they fit in the “avails” that are agreed upon between the programmer and operator), but typical lengths are 30 second, 60 seconds, or 15 seconds.

Cable operators typically have the right to insert local messages on a variety of different networks. In addition to this, typical cable systems consist of multiple ad insertion zones (or ad insertion head ends). So if a cable operator serves an area (say a city) that consists of <n> insertion zones, and wants to insert commercial messages on <m> different networks, a total of <n>×<m> ad inserters are needed. This enables the operator to insert unique (different) commercial messages in each zone/network combination, but at a high cost for equipment.

With the introduction of digital television, cable operators now need to upgrade their insertion infrastructure in order to be able to insert commercial messages into already compressed (digital) feeds. This new system (called DPI, or Digital Program Insertion) is illustrated in FIG. 3. The programmer typically distributes their feed via satellite 22 to the various cable operators. The feed is digitally encoded. The feed contains signals (in the form of special messages, such as the “SCTE 35” messages that are standardized for this purpose by SCTE) that indicate a local break to the cable operator.

The receiver at the cable operator receives the satellite signal and passes it through (including the digital messages) to a new device called a splicer 34. The splicer 34 (among other things) will detect the digital messages in the stream 33, and start an interaction with the digital ad server 36 to get a digitally encoded commercial that is ready for insertion, it will then “splice” that digital commercial into the digital feed 33 during the local avail. The output signal 38 will be a digital signal with a local commercial during the local avail, and is distributed to digital reception devices at the consumers premises (typically a digital set-top box, or a digital TV set).

One of the reasons why digital insertion is more complex, is that insertion (splicing) of a digital commercial in a digital feed is not as straightforward as the simple “switch” that is embedded in the analog ad inserter 26 (see FIG. 2). Instead it needs a fairly sophisticated splicer 34, which is typically external to the ad inserter 26.

Scalability for digital insertion is similar to analog insertion, if a cable operator serves <n> insertion zones, and wants to insert commercial messages on <m> different digital networks, a total of <n>×<m> ad inserters and splicers are needed. Again, this enables the operator to insert unique (different) commercial messages in each zone/network combination.

One of the trends in local cable advertising is to combine all ad insertion zones and capabilities into a single “Interconnect”. An Interconnect typically covers a complete city and may consist of one cable operator, or even a combination of multiple cable operators. It essentially connects all ad inserters so that a client (e.g. an advertiser) can approach the whole market as a single entity, can place single orders, and there is a single T&B (traffic and billing) system driving the insertion schedules. In addition the technical part of the interconnect is typically run from a single command location (Master Control Center). If an Interconnect covers <n> zones, it has the ability to (in any given local avail) air <n> different commercials at the same time in the same program.

There is a large cost involved in converting to digital. Cable operators that “go digital” (in other words: start to distribute their signals to their subscribers in digitally compressed format) obviously face significant investments in infrastructure, digital set-top boxes or other CPE, etc. But on top of these, there is another required investment which is sometimes overlooked, namely the equipment that is needed to insert commercial messages into compressed (digital) program feeds. For a market that contains <n> zones and <m> digitally carried networks, this may add up to <n>×<m> splicers and <n>×<m> digital ad servers, which can be a significant investment.

Therefore, many operators consider “collapsing” their insertion zones to save money (e.g. collapse <n> zones into one (or few) big insertion zones). This reduces investment, but also reduces the unique ability to insert different commercials in different zones (which advertisers can use for reasons of better targeting their messages).

SUMMARY

The present invention provides some alternative approaches to digital commercial insertion for cable operators and others that not only offer more flexibility and features, but may also be significantly cheaper to implement. In one embodiment, the present invention includes a system where the actual “insert” of the commercial or message into the digital program is actually performed by the digital receiver that sits at the consumer's premises (this can be a set-top box, digital TV set, or other). This strongly reduces the need for sophisticated splicer and ad-server equipment at the head-end, while imposing minimal to no additional cost at the receiver devices.

In another embodiment, the present invention includes a system where the actual “insert” of the commercial is performed upstream (for example, at the head-end), yet the number of unique splicers and ad servers is greatly reduced, while preserving the ability to send insert different commercials in different insertion zones.

The present invention includes a method of inserting local commercials into a local feed, including receiving and distributing a digital media stream to a plurality of digital reception devices (for example, set top boxes), detecting a signal in the digital media stream indicating an insertion point, selecting a digitally encoded commercial for insertion; and sending the digitally encoded commercial to the plurality of digital reception devices, at a time as indicated by the signal indicating an insertion point. It further includes providing a signal to at least some of the plurality of digital reception devices to indicate to the some of the plurality of digital reception devices to switch to the digitally encoded commercial. The digital reception devices will switch back to the digital media stream at a time after an end time of the digitally encoded commercial. The digital reception devices may be provided with software to facilitate switching to and from the digitally encoded commercial, or may be hardcoded with firmware, Asics etc. to allow the switching functionality.

The step of sending the digitally encoded commercial to the plurality of digital reception devices may be performed by multiplexing the digitally encoded commercial into the digital media stream. Alternatively, it can be performed by using a feeder channel, or a combination of these techniques.

Some of the digital reception devices may receives a different digitally encoded commercial, depending on the setup of the system. For example, a plurality of digitally encoded commercials may be sent simultaneously to the plurality of digital reception devices, and a filtering process will filter out at least one digitally encoded commercial to prevent it from being received by a selected group of digital reception devices.

A count may be maintained of a number of times the digital reception devices switch to the digitally encoded commercial, and a different digitally encoded commercial may provided depending upon the count.

The present invention also includes a system for inserting local commercials into a local feed. A client ad server component, receives a digital media stream and distributes the digital media stream to a plurality of digital reception devices. When the client ad server component detects a signal in the digital media stream indicating an insertion point, the client ad server component sends a digitally encoded commercial for insertion to the plurality of digital reception devices, at a time as indicated by the signal indicating an insertion point. The client ad server component provides a signal (which may be the same signal as the signal indicating an insertion point, just passed on through) to at least some of the plurality of digital reception devices to indicate to those plurality of digital reception devices to switch to the digitally encoded commercial. The digital reception devices will switch back to the digital media stream at a time after an end time of the digitally encoded commercial.

Another aspect of the present invention includes a system for allowing a plurality of different local messages to be inserted across a plurality of insertion zones. It includes a plurality of splicing components, one splicing component for each different local message, wherein the plurality of splicing components receiving a common network feed. It also includes a programmable switch, having an input port for each of the plurality of splicing components, and having an output port for each of the plurality of insertion zones, wherein the programmable switch is capable of mapping any input port to one or more output ports. A controller controls the plurality of splicing components and the programmable switch, to allow a different local message to be provided to a selected ones of the plurality of insertion zones. The controller can include a prioritizing function to determine the best allocation of local messages to insertion zones in case there are more local messages than splicing components.

This aspect of the invention may also include a initial switch providing the common network feed to the plurality of splicing components, the initial switch to provide for changing the common network feed to a network feed which will subsequently include an insertion point for inserting local messages. Before a local message is complete, the controller can instruct the programmable switch to cause at least one insertion zone to start receiving media from a different splicing component.

An advantage of the present invention include the ability to use present-day set top boxes with minimal “intelligence”, for example, without any need for a profiler to help such set top box to decide which local commercial to insert.

Other advantages of the present invention include a more cost efficient way of digital commercial insertion for cable operators and others, but also an approach that inherently provides more flexibility (for example, there is no reason anymore why commercial insertion zones need to be “hard wired” and not change-able once they are done).

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and advantages of the present invention will be more fully understood from the following detailed description of illustrative embodiments, taken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a traditional local cable ad insertion system;

FIGS. 2A and 2B illustrate pass-through and Ad Inserter mode for a traditional ad inserter;

FIG. 3 illustrates a digital local cable ad insertion (DPI);

FIG. 4 shows an illustrative embodiment of the present invention for Client Insertion;

FIG. 5 illustrates how to insert Commercials Within Multiplex according to an illustrative embodiment;

FIG. 6 illustrates how to use Feeder Channel according to an illustrative embodiment;

FIG. 7 illustrates a Shared Feeder Channel example;

FIG. 8 illustrates a Unique Feeder Channels Per Zone example;

FIG. 9 illustrates a Cascaded Approach example;

FIG. 10 is a block diagram of a Client Ad Server Unit (CASU) according to an illustrative embodiment;

FIG. 11 is a block diagram illustrating Signal Paths for Digital Insertion; and

FIG. 12 illustrates an embodiment for Optimized Digital Insertion.

DETAILED DESCRIPTION

The present invention provides a novel solution to allowing local insertion of content, typically local commercials or ads, into the digital feed for cable operators and other distributors. The present invention may be implemented at several different locations along the delivery process, either in one location or distributed along the delivery stream. Although the present invention is described in terms of commercials and ads, the present invention can be used for insertion of any specific media, such as messages intended for a local audience, or even customized parts of generic commercials, such as the insertion of a local store location at the end of a generic commercial.

An illustrative embodiment of the present invention focusing on using Set-top boxes for insertion shall now be described. In this approach, the insertion (splicing) of commercial messages is pushed down to the individual digital set-top boxes 44 as illustrated in FIG. 4. The programmer distributes their (digitally encoded) feed (including SCTE 35 or other switch messages to signal local avails) via satellite 22 (or by other method) to the various cable operators. The receiver 32 at the cable operator receives the satellite signal and passes it through (including the digital switch messages) to a new device called “Client Ad Server” 40.

The Client Ad Server 40 stores commercials for later play out. Typically such commercials are already in digital form, and compressed. The Client Ad Server 40 also communicates with the Traffic & Billing system 42 so that it understands which commercials are schedule for each local avail. Whenever the Client Ad Server 40 detects a digital insert message (e.g. SCTE 35 message) in the stream 33, it does the following:

-   -   Locates a commercial that should be “inserted” in this break,         and play it out exactly in sync with the avail (either in the         same multiplex, or on a separate multiplex, as described below).     -   Either passes through the digital insert messages to the set-top         boxes 44 downstream, or alternatively replaces them with similar         switch messages specifically designed to be handled by set-top         boxes 44.

The Set-top boxes 44 are typically ordinary set top boxes, which include special switching logic, typically in the form of an embedded software application. This embedded software may be installed the Set-top boxes 44, or alternatively downloaded to the Set-top boxes 44 through the digital feed 35 or otherwise. The software detects switch messages in the stream 35, and uses them to “switch” to a local commercial during the insertion break. More specifically, in accordance with an illustrative embodiment, at the beginning of an avail the Set-top boxes 44 will switch to the local commercial, and at the end of a specified length of time they will switch back to the program feed 35.

When the Client Ad Server 40 plays out the local commercial exactly in sync with the local avail of the program it needs to be inserted into, there are two options for provided the commercial to the set-top boxes 44. The first option is shown in FIG. 5, where the local commercials are be played out in the same multiplex as the program feed it needs to be “inserted” into. FIG. 5 illustrates a single (MPEG) multiplexed signal 45 that carries six digital program feeds 46 (for this example, ESPN, CNN, USA, TNT, TBS, A&E). These program feeds are merely illustrative and no claim is made to those networks or any affiliation with any such network. The multiplex 45 also has two reserved feeds 48 that are only used during a local avail on any of the six programs 46. Precisely during each of these local avails 50, the reserved feed 48 will carry the local commercial 52 so that the set-top boxes 44 (not shown) can “switch to” and “switch from” the commercial 52 at the beginning and end of the avail 50 respectively.

This approach requires some bandwidth to be reserved in every multiplex 45 that carries digital programs 46 that need local ad insertion. The amount of bandwidth depends on how many overlapping local breaks 50 can occur amongst the digital program feeds 46 within the multiplex 35, in the example there are two reserved feeds 42 so its is possible to handle up to two overlapping avails 50. Other numbers of reserved feeds 42 are possible and within the scope of the invention. Further, there is some room for optimization beyond the number for reserved feeds 42, for example it may be a good idea to concentrate the most valuable program feeds 46 in few multiplexes 45 that have a relatively high number of reserved feeds (for example, four), whereas the less valuable program feeds 46 are carried in multiplexes 45 with lower number of reserved feeds. This would have the effect that the chances of “losing” an avail on valuable feeds 46 is less than loosing an avail on a less valuable network 46.

The second option is shown in FIG. 6 and involves playing the local commercials in a dedicated feeder channel. FIG. 6 illustrates a number (in this case four) of MPEG multiplexes 45. The first three multiplexes (Mux 1-3) carry regular digital program feeds 46 (depending on encoding and modulation, there typically may be as few as seven, or more than twelve program feeds in the multiplexes). The fourth multiplex, Mux-4, is reserved for all local commercials, it is also known as the feeder channel.

The regular program feeds contain local avails 50. Precisely during each of these local avails, the feeder channel Mux-4 will carry the local commercial 52 so that the set-top boxes can “switch to” and “switch from” it at the beginning and end of the avail 50 respectively.

The feeder channel can either be a fully dedicated multiplex/QAM (Quadrature Amplitude Modulation), but it can also be a reserved part of a multiplex/QAM that is partly also used for other services. The amount of bandwidth that has to be reserved in the feeder channel depends on how many overlapping local avails the operator wants to be able to handle with this system. This allocation can be fine-tuned by the cable operator as a trade off between bandwidth and returns.

Each of these embodiments has certain advantages. The first embodiment, within the multiplex 45 has the advantage very simple implementation in set-top box, and can do a cleaner (seamless) splice even with basic set-top boxes. However, it tends to use more bandwidth and may require more sophistication at the head-end, because of the need for re-multiplexing instead of simple play out. The second embodiment, using a feeder channel, has optimal bandwidth efficiency. However it may require more integration in set-top box software (for example, the need to access the tuner). Also, a seamless splice is somewhat more difficult, however this can be fixed by having black frames around the commercial. It is also possible to mix both approaches to achieve the best combination of simplicity, bandwidth efficiency, and other features for a general solution, and also specific requirements.

Focusing now on the Client Ad Server 40, there are a number of different options on the number and location of Client Ad Servers 40 in the cable operators network. In a first centralized example, consider a cable operator in a market that has 50 insertion zones, and 40 networks feeds that require local commercial insertion. We assume that the cable operator uses the Feeder Channel approach to preserve bandwidth. The cable operator may decide to use 40 Client Ad Servers (one for each network feed) and place them at a central location in the system (for example the Master Control Center) to feed all insertion zones.

Now let's look at a local avail 50 FIG. 7 in one of the network feeds 46 (say ESPN). Let's assume the cable operator wants to insert 10 different commercial messages 52 in this local break (one in zones 1-5, one in zones 6-10, etc.). Since there is only one Client Ad Server (not shown) that is shared between all 50 insertion zones, the (bandwidth in the) Feeder Channel 45 d is also shared. In this scenario the individual set-top boxes will be instructed which commercial message to select (which will depend on the insertion zone they are member of).

Turning now to a decentralized option, the system can be implemented with a Client Ad Server 40 per insertion zone (so for this example, fifty in total). In the same local insertion example (ESPN, ten commercials) each of the Client Ad Servers 40 will only insert one commercial 52 in the Feeder Channel (namely the one that is intended for its specific insertion zone), as illustrated in FIG. 8. In this scenario, the set-top box does not need specific (zone dependent) instructions in order to “pick” from multiple local commercials 52, making this implementation simpler.

A final example shown in FIG. 9 provides a cascaded approach, where a single Client Ad Server 40 per network feed is used in combination with a number of “filter” units 56 downstream to optimize bandwidth usage. This approach puts a single Client Ad Server 40 (per network feed) in a central location (similar to example 1), which would transmit a feeder channel with all different local commercials in it over the backbone network 54 to each head-end or node 55 (similar to FIG. 7). However at the head-end or node 55 (where the backbone network terminates and is connected to the “Last Mile” coax network 58) a special filter 56 strips the feeder channel from all local commercials but the one that is relevant for this insertion head end 55, so the actual feeder channel that is transmitted to the individual homes looks like FIG. 8. Examples of filter units 56 may be an existing edge device such as an edge-QAM modulator, that simply only passes one of the feeder channels through, ignoring all others. It could know which one to pass through by configuring it at installation time, so every QAM would be configured to “pass” unique feeder channels). Other possible approaches are also within the scope of the invention.

An advantage of this setup is only one Client Ad Server 40 is needed per network feed, and the Set Top Box does not need specific (zone dependent) instructions for picking the proper local commercial.

An illustrative implementation is a cascaded approach with a feeder channel. In this implementation, a single Client Ad Server Unit (CASU) 60 is installed at a central location in the cable operators network (e.g. at the Master Control Center). The CASU 60 FIG. 10 performs the following tasks:

-   -   It passes through all digital program feeds 46 of programs that         have local avails, and detects incoming insert messages (it also         passes these insert messages through, or generate set-top box         specific ones, as previously described).     -   It manages the Central Feeder Channel 62 (which is carried to         each head-end over the backbone network), and plays out all         required local commercials on the Feeder Channel 62 during each         relevant local break     -   It has a network interface 64 for loading/unloading new         commercial messages that it (may) need to insert locally.     -   It has an interface to Traffic & Billing systems 42, so that it         knows which local commercials should be inserted across the         whole market in a specific break. It can also maintain logs of         which local commercials have been viewed a certain number of         times (broken down by zone, if helpful), and can choose to         substitute/rotate through different commercials based on any         desired formula.         The CASU 60 functions as follows:     -   There is an interface 64 for loading new local commercials onto         the CASU 60, and removing commercials off of the CASU 60 when         they are no longer needed. Local commercials are loaded in         digitized form and stored 68. This interface can be driven by an         asset management system, or by a local operator. Local         commercials are given a unique identifier when loaded on the         CASU.     -   The T&B System 42 has a dedicated interface for loading         scheduling information into the CASU 60. This information         basically defines which local commercial needs to be inserted in         which feed under which conditions (time, etc.). The CASU 60         stores this scheduling information in its internal schedule         database 66.     -   Up to forty network program feeds 46 can enter the CASU 60.         Although forty feeds 46 were chosen because cable operators         typically insert into forty networks only, this selection is         arbitrary and can be any number of feeds. These feeds 46 may         contain digital insert messages to signal a local avail. The         CASU 60 will pass through the feeds and whenever there is a         local avail, it will access its internal database 66 to         determine which local commercials need to be inserted, and play         these commercials on the Central Feeder Channel output port 62         exactly during the local avail. In addition it may also be         necessary to send some additional information to the set-top         boxes downstream (either by inserting additional information in         the program feeds, or otherwise), this information may include         where in the central feeder channel 62 the local commercials are         played out. The forty input feeds, forty output feeds, and         central feeder channel output feed can physically be mapped on         connectors such as DVB-ASI, DVB-DHEI, or any other interface. It         is also possible to map/combine multiple logical inputs and/or         outputs into one physical connector.     -   The CASU 60 will also manage bandwidth of the central feeder         channel. For example if the system only has bandwidth to deal         with <n> overlapping local commercials, and there actually are         more than <n> overlapping commercials scheduled, it may either         request additional bandwidth or select the <n> local commercials         that can be served. It can do that based on simple         “First-Come-First-Served” selection, or based upon more         sophisticated algorithms that select the commercials with the         highest value.

A second useful component of this system is a Filter Unit 56 FIG. 9 that sits in each insertion zone. It simply takes the central feeder channel 62 FIG. 10 as an input (containing all different local commercials during each break) and strips out all but the one that is intended for this insertion zone. It produces a Local Feeder Channel that is then transmitted to the homes (and set-top boxes) in the zone. The filter unit 56 basically makes the Set top box's job simple by avoiding needing the set top box to have intelligence to pick the correct insertion commercial.

Another component of this system is a software application that resides in the set-top box 44. The application can be resident or downloadable, it does not have a user interface, does not need a return channel per se, and performs the following functions:

-   -   When started the application goes into “passive mode” and starts         “listening” to digital insert messages in the current program         feed.     -   Whenever an insert message is detected, the location of the         local commercial in the local feeder channel is retrieved.         Examples of retrieval include providing the commercial with the         insertion message, or the commercial can be communicated to the         set top box separately. The application retunes the set-top box         to that local commercial at the start of the local avail, and         tunes back to the original program feed at the end of the local         avail. Typically, this will all be transparent to the user.

Another embodiment of the present invention is based on the notion that the current network topology (with individual inserters per insertion zone) is in many cases may be overkill. FIG. 11 shows the signal paths for digital insertion in a single program feed by a cable operator that has <n> insertion zones (for the sake of simplicity each combination of a splicer 34 and a digital ad server 36 is represented as a single box)

This setup gives the cable operator the ability to insert (in a given local avail) a unique and different local commercial in each insertion zone. In reality however, in most cases the cable operator will either insert the same local commercial in all zones, or only a limited set of different local commercials mapped on the various insertion zones (for example in a market with fifty insertion zones, there may be five different commercials, the first going to zones 1-10, the second one going to zones 11-20, etc.). Another way of saying this is that in the traditional setup of ad insertion (such as in FIG. 11) the system is dimensioned for the worse case usage scenario, but does not take advantage of the fact that statistically the cable operator will only use a fraction of that.

An alternative setup for digital program insertion according on an embodiment of the present invention is shown in FIG. 12. This setup allows for a maximum of <m> different local commercials to be inserted across <n> insertion zones. This setup consists of the following components:

-   -   A total of <m> splicer/ad-server combinations 34, 36 are set up,         all connected to the incoming program feed.     -   A programmable switch 70 is set up. It has <m> input ports 72,         and <n> output ports 74, and can be programmed to map any input         port onto any combination of output ports. Its input ports are         connected to the output ports of the splicers 34,36. Its output         ports are connected to each insertion zone.     -   A controller 76 is provided. It interfaces with the T&B system         42 on one hand, and with the splicer/ad-servers 34, 36 and         programmable switch 70 on the other hand.         The system operates as follows:     -   The T&B System 42 communicates scheduling information to the         controller 70, who stores this in its internal database.     -   Whenever there is a local avail, the splicers 34 will detect it         (through the presence of digital insertion messages) and inform         the controller 76.     -   The controller 76 will then determine which local commercials         need to be inserted in which insertion zones, and assign each         unique local commercial to exactly one splicer/ad-server 34, 36         pair. The controller 76 will also program the switch 70 so that         the output of each splicer 34 is mapped to the correct insertion         zones.

Because of time and scheduling, the controller 76 typically will know in advance when a local avail is coming up, and can ‘preprogram’ the switch 70 to divide up the interzones by appropriate splicer 34. This setup may be left in place until a next local avail comes up which has a different combination of commercials or insertion zones. Since the splicers 34 are passive when not inserting local commercials, the system will run normally during normal broadcast, no matter how switch 70 has mapped the splicers 34 to insertion zones.

This embodiment is flexible with respect to the choice of the maximum number of unique commercials. Obviously a lower number will create greater cost savings but will also limit flexibility. If in a system with fifty insertion zones (n=50) it would be acceptable to set the maximum number of unique commercials to ten (m=10), this system would create an 80% cost savings on splicer/ad-server pairs when compared with the traditional setup. Further, it is expandable on an incremental basis.

In this embodiment, some of the components may be combined into other physical system components. For example the programmable switch 70 may be a separate unit, or integrated with the controller 76, or even be an integral part of the network (depending on what network is used to distribute program feeds to the insertion zones, this may already be a feature that is built into that network). It should be noted that it is also possible to combine these various approaches to create unique trade offs between investment, features, etc. It should be noted that the present invention can be combined with features described in other pending commonly owned patent applications, including U.S. patent application Ser. No. 09/735,983, entitled Seamless Switching and filed on Dec. 13, 2000; U.S. patent application Ser. No. 10/369,047, entitled Seamless Switching and filed on Feb. 19, 2003; U.S. patent application Ser. No. 10/192,192, entitled System And Method For Seamless Switching Of Compressed Audio Streams and filed on Jul. 9, 2002; U.S. patent application Ser. No. 10/423,280, entitled System And Method For Optimized Channel Switching In Digital Television Broadcasting and filed on Apr. 25, 2003; and U.S. patent application Ser. No. 10/991,674, entitled System And Method For Optimized Encoding And Transmission Of A Plurality Of Substantially Similar Video Fragments and filed on Nov. 18, 2004; which are fully incorporated here by reference.

Although this description is written from the perspective of a cable operator, it is straightforward to apply the same approaches to other network operators as well (for example broadcast networks with affiliates, cable networks with local reception points at head-ends, etc.).

Although the invention has been shown and described with respect to illustrative embodiments thereof, various other changes, omissions and additions in the form and detail thereof may be made therein without departing from the spirit and scope of the invention. 

What is claimed is:
 1. A method of inserting local commercials into a local feed, comprising: receiving and distributing a digital media stream to a plurality of digital reception devices; detecting a signal in said digital media stream indicating an insertion point; selecting a digitally encoded commercial for insertion; sending said digitally encoded commercial to said plurality of digital reception devices, at a time as indicated by said signal indicating an insertion point; providing a signal to at least some of said plurality of digital reception devices to indicate to said some of said plurality of digital reception devices to switch to said digitally encoded commercial; and wherein said some of said plurality of digital reception devices will switch back to said digital media stream at a time after an end time of said digitally encoded commercial.
 2. The method of claim 1 wherein said digital reception devices are set top boxes.
 3. The method of claim 2 wherein said set top boxes are provided with software to facilitate switching to and from said digitally encoded commercial.
 4. The method of claim 1 wherein said step of sending said digitally encoded commercial to said plurality of digital reception devices is performed by multiplexing said digitally encoded commercial into said digital media stream.
 5. The method of claim 1 wherein said step of sending said digitally encoded commercial to said plurality of digital reception devices is performed by using a feeder channel.
 6. The method of claim 1 wherein other ones of said plurality of digital reception devices receives a different digitally encoded commercial.
 7. The method of claim 1 wherein a plurality of digitally encoded commercials are sent simultaneously to said plurality of digital reception devices, and further including the step of filtering out at least one digitally encoded commercial to prevent it from being received by a selected group of digital reception devices.
 8. The method of claim 1 wherein a count is maintained of a number of times said digital reception devices switch to said digitally encoded commercial, and a different digitally encoded commercial is provided depending upon said count.
 9. A system for inserting local commercials into a local feed, comprising: a client ad server component, to receive a digital media stream and to distribute said digital media stream to a plurality of digital reception devices, wherein when said client ad server component detects a signal in said digital media stream indicating an insertion point, said client ad server component sends a digitally encoded commercial for insertion to said plurality of digital reception devices, at a time as indicated by said signal indicating an insertion point, and wherein said client ad server component provides a signal to at least some of said plurality of digital reception devices to indicate to said some of said plurality of digital reception devices to switch to said digitally encoded commercial; and wherein said some of said plurality of digital reception devices will switch back to said digital media stream at a time after an end time of said digitally encoded commercial.
 10. The system of claim 9 wherein said digital reception devices are set top boxes.
 11. The system of claim 10 wherein said set top boxes are provided with software to facilitate switching to and from said digitally encoded commercial.
 12. The system of claim 9 wherein said client ad server component sends said digitally encoded commercial to said plurality of digital reception devices by multiplexing said digitally encoded commercial into said digital media stream.
 13. The system of claim 9 wherein said client ad server component sends said digitally encoded commercial to said plurality of digital reception devices by using a feeder channel.
 14. The system of claim 9 wherein other ones of said plurality of digital reception devices receives a different digitally encoded commercial.
 15. The system of claim 9 wherein said client ad server component sends a plurality of digitally encoded commercials simultaneously to said plurality of digital reception devices; and wherein a filtering component receives said digital media stream from said client ad server component, said filtering component removing at least one digitally encoded commercial to prevent it from being received by a selected group of digital reception devices.
 16. The system of claim 9 wherein a count is maintained of a number of times said digital reception devices switch to said digitally encoded commercial, and a different digitally encoded commercial is provided depending upon said count.
 17. A system for allowing a plurality of different local messages to be inserted across a plurality of insertion zones, comprising: a plurality of splicing components, one splicing component for each different local message, wherein said plurality of splicing components receiving a common network feed; a programmable switch, having an input port for each of said plurality of splicing components, and having an output port for each of said plurality of insertion zones, wherein said programmable switch is capable of mapping any input port to one or more output ports; and a controller, to control said plurality of splicing components and said programmable switch, to allow a different local message to be provided to a selected ones of said plurality of insertion zones.
 18. The system of claim 17 wherein said controller includes a prioritizing function to determine the best allocation of local messages to insertion zones in case there are more local messages than splicing components.
 19. The system of claim 17 further including a initial switch providing said common network feed to said plurality of splicing components, said initial switch to provide for changing said common network feed to a network feed which will subsequently include an insertion point for inserting local messages.
 20. The system of claim 17 wherein before a local message is complete, said controller instructs said programmable switch to cause at least one insertion zone to start receiving media from a different splicing component. 